Conservation of Energy
Energy transformation in a simple
pendulum
Kinetic energy is maximum at the bottom of
the pendulums arc
Potential energy is highest at the top of the
pendulums arc
Dropping object
Question
A rock is raised to a height where it has
2
Kinetic Energy
W = F*d
W = mad
a = (vf2 vi2)/2d
W = mvf2 mvi2
Kinetic Energy, and the Work-Energy Principle
If we write the acceleration in terms of the velocity and the distance, we find that
the work done here is
We define the kinetic energy:
Example
Ho
Levers
The fulcrum is the pivot point of the lever, there are three basic
types of levers.
In all three cases the mechanical advantage is the ratio of the
distance to the fulcrum where force is applied to the distance from
the load to the fulcrum. Note th
Machines
A machine is a device used to multiply
forces or change the direction of force.
three simple machines are ramps, levers,
and pulleys.
Ramps
A ramp is a simple machine it allows one
to move an object up without exerting the
force necessary to lift
Solar system
Solar System Viewer
http:/janus.astro.umd.edu/SolarSystems/
Weightlessness
Earth-orbiting
astronauts are
weightless for the
same reasons that
riders of a freefalling amusement
park ride or a freefalling elevator are
weightless. They
are weigh
Stopping Distance
To reduce the kinetic energy to zero:
so the stopping distance is
Note that this implies a stopping distance independent of vehicle
mass. It also implies a quadrupling of stopping distance with a
doubling of vehicle speed.
A rocket coast